Dishwasher

ABSTRACT

A dishwasher includes a washing container, devices for washing dishes by means of rinsing liquor, and a sorption drying device which is connected in an air-conducting manner to the washing container via an outlet of the washing container and an inlet of the washing container. The sorption drying device is provided with a sorption column encompassing reversibly dehydratable material and is disposed between a wall of the washing container and an exterior housing wall of the dishwasher.

The invention relates to a dishwasher with a washing container and devices for washing dishes by means of rinsing liquor and with a sorption drying device which is connected in an air-conducting manner to the washing container via an outlet of the washing container and an inlet of the washing container, and is provided with a sorption column encompassing reversible dehydratable material.

As is known, conventional dishwashers perform a washing process whose programme sequence generally consists of at least one “Pre-wash” partial programme step, a “Clean” partial programme step, at least one “Intermediate wash” partial programme step, a “Clear wash” partial programme step and a “Dry” partial programme step. To increase the cleaning effect the rinsing fluid or rinsing liquor is heated before or during a partial programme step. The rinsing fluid is normally heated by means of electrical heating elements. Different drying systems are known for drying the items to be washed in a dishwasher.

DE 20 16 831 discloses, for example, a dishwasher of the type already mentioned in which the air is conducted from the washing container through a sealable opening in the wall of the washing container on reversibly dehydratable material, and from there to the outside through an opening. Desorption of the reversibly dehydratable material takes place during the non-operating phase of the device, the water vapour formed thereby being conducted to the outside through the opening. The dishwasher described is disadvantageous from the energy viewpoint because the regeneration of the reversibly dehydratable material takes place during a non-operating phase of the appliance, i.e. at a time when none of the partial programme steps already described is being carried out. A further disadvantage consists in the fact that the possibility of damage to the surrounding kitchen furniture cannot be ruled out as a result of the discharge of the water vapour formed during regeneration of the reversibly dehydratable material to the outside. In this case the regeneration is associated with an additional energy requirement which is additional to the energy required during the partial programme steps.

In order to minimise the energy expended during operation of a dishwasher, DE 103 53 774.0 of the applicant discloses a dishwasher with a washing container and devices for washing dishes by means of rinsing liquor which is provided with a sorption column which is connected in an air-conducting manner to the washing container and encompasses reversibly dehydratable material, where on the one hand the sorption column is used for drying the dishes and on the other hand the thermal energy utilised for desorption of the sorption column is used to heat the rinsing liquor and/or the dishes in the washing container, at least in part.

To solve the same problem DE 103 53 775.9 of the applicant proposes conducting air from a processing space and/or from ambient air through a sorption column and into the processing space for operating an appliance in the at least one “Dry” partial programme step, where the sorption column encompasses reversibly dehydratable material and moisture is extracted from the air during its through-passage.

Heating the items to be washed in the partial programme step preceding the “Dry” partial programme step is no longer normally necessary due to the use of reversibly dehydratable material with a hydroscopic property, e.g. zeolith. This allows a substantial saving in energy.

EP 0 358 279 B1 discloses a dishwasher with a closed drying system in which the air from the washing container circulates through a drying device that can be regenerated by heating and from this device back into the washing container. The drying device is assigned to the heater arranged outside the washing container for the rinsing liquor, this heater preferably being a geyser. The outlet of the washing container is located in the ceiling of the washing container, whilst the inlet is integrated in the rinsing tank of the washing container. The outlet of the washing container is connected to the sorption drying device by means of an air duct. Since the sorption drying device is assigned to the heater for the rinsing liquor it is arranged in a region underneath the rinsing tank.

A common feature of all the arrangements described above is that the integration of the sorption drying device in a dishwasher is only conceptually described. The object of this invention is therefore to provide a dishwasher in which a sorption drying device can be integrated easily and at low cost.

This object is achieved with a dishwasher having the features according to Claim 1. Advantageous further developments of this invention are indicated in the dependent claims.

A dishwasher according to the invention, particularly a domestic dishwasher, has a washing container and devices for washing dishes by means of a rinsing liquor, as well as a sorption drying device which is connected in an air-conducting manner to the washing container via an outlet of the washing container and an inlet of the washing container, and which is provided with a sorption column encompassing reversibly dehydratable material. Here the sorption drying device is arranged between a washing container wall and an outer housing wall of the dishwasher.

According to one design the sorption column is used for drying the dishes on the one hand and the thermal energy utilised for desorption of the sorption column is used for heating the rinsing liquor in the washing container and/or the items to be washed on the other. The dishwasher can be designed, in terms of its operating principle, as described in DE 103 53 774.0 and/or DE 103 53 775.0 of the applicant, the contents of which are incorporated in this application where appropriate. The machine described here differs in terms of a preferred arrangement of the sorption drying device.

According to a preferred feature, air is conducted from the washing container and/or from the ambient air during a partial programme step with rinsing liquor to be heated, preferably during the “Clean” and/or “Pre-wash” and/or the “Clear wash” partial programme step through the sorption column and back into the washing container

An electric heating element is suitably arranged for desorption of the reversibly dehydratable material and for heating the rinsing liquor and/or the items to be washed.

In a suitable design the sorption column, and optionally the electrical heating element, are arranged concentrically around the outlet and/or the inlet. Because of the concentric design a particularly low overall height and hence a particularly space-effective design of the sorption drying device are achieved. Moreover, the arrangement of the functional elements arranged underneath the rinsing tank need not be modified relative to conventional dishwashers. The outlet is located in a lateral wall. The inlet, or even a plurality of inlets, may be arranged in the same washing container wall, in the rinsing tank or in the washing container ceiling. The first-mentioned variant here offers the advantage of an extremely simple structural design, sine the installation of air ducts may be largely dispensed with. On the other hand the provision of air ducts offers the advantage, already mentioned, that the condensation area is designed so that the sorption column of the sorption drying device can be generally constructed much smaller.

The electrical heating element is preferably arranged in the reversibly dehydratable material or in a pipe to the sorption column.

According to a further suitable design the outlet and/or inlet is/are provided with a passive means for sealing against penetrating water in the simplest case this may be cover over the outlet and/or inlet which is preferably designed so that at the same time the direction of the air flow is established to achieve the best possible turbulence of the air in the washing container for effective moisture absorption.

In an alternative design the outlet and/or the inlet may be provided with active sealing means. The sealing means may be designed, for example, so that it can be actuated by applying a voltage. The sealing means may therefore be designed so that it is motor or hydraulically driven. It is particularly advantageous here if voltage is also applied to the sealing means when voltage is applied to the fan, enabling the sealing means to open to provide air circulation to the sorption drying device. Here the inlet and outlet need only be open during the regeneration phase of the sorption column and during the “Dry” partial programme step. During the other partial programme steps the sealing means provide such sealing to prevent spray water from penetrating the sorption drying device provided with electrical functional elements.

In a further suitable design the sealing means may also be actuated by a temperature-sensitive memory metal. Here the sealing means is not actuated electrically but on the basis of the temperatures prevailing during different partial programme steps.

The invention is explained in further detail in the following with reference to a FIGURE in which is shown an exemplary embodiment of a dishwasher according to the invention.

The FIGURE shows, in a diagrammatic representation, a dishwasher 1 of the invention with a washing container 2, in which are arranged crockery baskets, not shown, for the storing of items to be washed, not shown either. Dishwasher 1 is provided with a sorption column 10 which is connected in an air-conducting manner to washing container 2 and encompasses reversibly dehydratable material 11, sorption column 10 being used on the one hand for drying and on the other hand for heating air passed through. Washing container 2 has an outlet 5 which is arranged in the exemplary embodiment described in a central region and an inlet 8 arranged in the exemplary embodiment described close to a rinsing tank 6, which inlet is connected by a pipe designed as an air duct 17 to sorption column 10. In addition to sorption column 10, a sorption drying device 21 has a fan (not shown) and a heating element 12. The passage of air through sorption drying device 21 is denoted by arrows A, B and C.

Sorption drying device 21 is arranged between a washing container wall 22 and an outer housing wall 23, electric heating element 12 and sorption column 10 being arranged concentrically around outlet 5. This provides a particularly space-saving arrangement since no additional space, in which all the functional components of a dishwasher are normally arranged, is taken up underneath the rinsing tank. Outlet 5 is located in this exemplary embodiment in the centre of washing container wall 22. Merely by way of example a single inlet 8 is shown which is located underneath sorption drying device 21 in the lower region of washing container wall 22 and is connected to it by means of an air duct 17.

According to another design a multiplicity of inlets 8 could be provided, which are arranged, for example, concentrically around outlet 5.

In a further variant inlet 8 could also be arranged in the rinsing tank or in the washing container ceiling.

Contrary to the previous description, the outlet identified in the FIGURE by reference number 5 could also represent an inlet of sorption drying device 21, in which case the inlet identified in the FIGURE by reference number 8 would then represent the outlet of sorption drying device 212. AS a result the outlet of washing container 2 would be connected by air duct 17 to sorption column 10.

Here air duct 17 could be designed as a condensation area, thereby reducing the amount of moisture contained in the moist air and enabling sorption column 10 to be dimensioned smaller.

The fan not shown in the FIGURE could be designed as an axial fan in the region of outlet 5, but in this variant adequate protection against penetrating spray water would have to be considered. Here an active sealing means could be provided, in particular, as described above. However, arranging the fan as a radial fan in air duct 17 would also be conceivable.

To prevent penetration of spray water into outlet 5, inlet 8 and hence the electrical functional parts (fan, heating element 12) of sorption drying device 21 during a partial programme step to which items to be washed are subjected, outlet 5 has a sealing means which may be designed as a passive sealing means in the form of a cover, e.g. with a flow function (not shown). Correspondingly inlet 8 has a sealing means 15 which may be designed, for example, as a cover with a flow function.

Both outlet 5 and inlet 8 could be provided with an actively actuated sealing means according to another variant, not shown either, which sealing means would be opened during the operation of sorption drying device 21 and closed in the remaining partial programme steps. Particularly advantageous here is a direct coupling to the operation of the fan and/or electric heating element 12. Thus the active sealing means could be actuated by means of a motor and/or hydraulically, the actuation being dependent on the operation of the sorption drying device. Alternatively the use of a memory metal would also be conceivable, which metal cold be brought into an opening or closing position according to the varying temperatures during different partial programme steps.

With this invention a dishwasher is provided which can be produced economically and with which the items to be washed in the washing container can be cleaned and dried efficiently, with the possibility of minimising the associated energy expenditure.

List of Reference Symbols

-   1 Dishwasher -   2 Washing container -   5 Outlet -   6 Rinsing tank -   8 Inlet -   10 Sorption column -   11 Reversibly dehydratable material -   12 Electrical heating element -   17 Air duct -   21 Sorption drying device -   22 Washing container wall -   23 Housing wall -   A,B,C Air passage 

1-11. (canceled)
 12. A dishwasher comprising: a housing having walls; a washing container having walls; at least one device for washing crockery using a rinsing solution; and a sorption column communicated with the washing container for the passage of air between the sorption column and the washing container, the sorption container containing reversibly dehydratable material that operates to withdraw moisture from air during the passage of the air through the sorption column, air passing from the washing container into the sorption drying device via an air inlet and thereafter flowing along a flow path through the sorption drying device and eventually exiting the sorption drying device via an air outlet, and the sorption drying device is arranged between a washing container wall and an outer housing wall of the dishwasher.
 13. The dishwasher according to claim 12, wherein, on the one hand, the sorption drying device is used to dry crockery being handled by the dishwasher and, on the other hand, thermal energy utilised for desorption of the sorption drying device is used to at least partially heat at least one of the washing solution in the washing compartment and crockery.
 14. The dishwasher according to claim 13, wherein air is conducted from the washing container and/or ambient air during a partial programme step with rinsing solution to be heated, preferably during the “Clean” and/or “Pre-wash” and/or “Clear wash” partial programme step through the sorption drying device and back into the washing container.
 15. The dishwasher according to claim 13, wherein an electrical heating element is arranged for desorption of the reversibly dehydratable material and for heating the washing solution and/or the items to be washed.
 16. The dishwasher according to claim 15, wherein at least one of the sorption drying device and the electric heating element is arranged concentrically around at least one of the outlet and the inlet.
 17. The dishwasher according to claim 15, wherein the heating element is arranged in a selected one of the reversibly dehydratable material and in a pipe leading to the sorption drying device.
 18. The dishwasher according to claim 15, wherein at least one of the outlet and the inlet is provided with a passive sealing means to prevent the penetration of water.
 19. The dishwasher according to claim 15, wherein at least one of the outlet and the inlet is provided with an active sealing means.
 20. The dishwasher according to claim 19, wherein the sealing means is actuated by the application of a voltage.
 21. The dishwasher according to claim 20, wherein voltage is applied to the sealing means by applying a voltage to a fan of the sorption drying device.
 22. The dishwasher according to claim 19, wherein the sealing means is actuated by a temperature-sensitive memory metal. 